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Feb. 1, 1949. E. B. LE FEVRE FILE Filed June 26, 1944 lllflrw PMN A Q w W l www www

MMM/WM J vue/Y (om 21971, @htm l Patented Feb. 1, 17949 FILE Edward Blair Le Fevre, Warwick, R. I., assigner to Nicholson File Company, Providence, lit. I., a corporation of Rhode Island Application June 26,1944, Serial No. 542,179

My present invention relates to les and particularly to illes of the type primarily intended to be manipulated manually in filing the surfaces of metallic or other objects.

The conventional file is relatively long and narrow and in the general case has a handle, or a tang or the like to which a handle may .be secured, at one end only. The teeth of the file face its leading end, i. e., that end of the le which is most remote from the handle end and, when the le is being manipulated inl the conventional manner, its user naturally moves it along a path, upon its working stroke, which has a forward component and a lateral component, the file moving forwardly or away from the operator and slightly to the left of Vthe users body, it being assumed that theoper-ator is right-handed. The natural stroke, therefore, is to sweep sidewise to some extent, the le, however, being generally maintainedV throughout its movemen-t with its axis in a constant direction, or substantially so. The natural working stroke is, therefore, such that not only one end of the file is constantly in advance of the other, and hence may be designated the leading end, but likewise one longitudinal edge of the le is constantly in advance of the other as the le moves slightly sidewise, such edge being conveniently designated the leading edge. In the design yof the le which comprises the present invention full consideration has been given to the fact that the lle when used will generally be manipulated with the natural stroke referred torand it has been so designed that its user will realize a num-ber of novel and important advantages.

The improved le has, for instance, .been so designed that it may perform both roughing and nishing operations upon a piece of work during a single ille stroke. Thus the leading margin of the le, which is that portion of the file surface adjacent its leading edge, is different in design from the trailing margin, or that portion of the le adjacent the opposite or trailing edge thereof, the leading margin being so constructed as to accomplish a roughing effect and the trailing margin constructed so asv-to primarily per form smoothing operations. This' is an advantage of considerable importance, insuring both rapid progress ln ling and a finished appearance. 'I'he le teeth are likewise Vso arranged that the tendency of the file to chatter as it passes `over a piece of Work is greatly reduced, without sa'crice in thev cutting ability of the le. Its design is such as to insure maximum removal of stock for a given pressure of the file 1 Claim. (Cl. ,2S-78) against the Work and likewise so as to minimize the tendency `of .the le to become clogged with small portions severed from the work. Y

The teeth of the le are arcuate and each of the arcuate teeth is divided into arcuate lands by notches or serrations. While it has heretofore been proposed that a file may be provided with arcuate teeth and that such teeth may be notched, the present invention provides a novel and improved arrangement 4of notched arcuate .teeth giving results not heretofore realized in the art. A preferred embodiment of the invention is illustrated in the accompanying drawings and will be described in detail. It will be appreciated by one skilled in the art that minor changes may be effected while at the same time maintaining the distinctive and advantageous features of the invention.

, In the drawings:

Figure 1 is a plan view of the file;

Figure 2 is an edge view of the same;

Figure 3 is a plan view of a portion of the file, upon a scale which is larger than that used in Figure 1;

Figure 4 is a section on line 4 4 of Figure 3; and

l Figure 5 is a section on line 5-5 of Figure 1.

The body of the le is of conventional shape and is indicated at i0 in the drawings, Abeing relatively long and narrow and having parallel or substantially parallel longitudinal edges. The tang is indicated at H. No handle is shown to be aixed to the tang, but it will be appreciated that the le may be provided with a handle if desired, or may be manipulated without the aid -of a handle portion, as its operatorchooses. The end of the file body which is remote from the tang H may be designated the leading end since the .le teeth face this end and .the le is pushed over the surface of the work, away from the 0perator and with this end in advance, when in normal use. In Figure 1 a portion of a piece of work is diagrammatically indicated at I2 and it will be understood that the work piece l2 must of necessity lbe considered to be above the file, it being 'necessary to illustrate .the iile with its work-engaging surface uppermost instead of turned, downwardly. Hence each area of the surface of the le. will move, as the lile is advanced on its natural working stroke, along some such path as indicated .by .the theoretically straight broken line A to be found in Figure 1. When so moving the axis of the le generally remainsv unchanged in direction, the lle in each .of its positions being approximately parallel to its previous and subsequent positions. The upper edge of the file, as .it is illustrated in Figure 1, may therefore be designated its leading edge since this edge leads the other edge over the surface of the work during any lateral movement of the le, and the opposite edge may be designated the trailing edge. Y

The file teeth are indicated at I3 and are, as previously stated, arcuate, with their convex sides facing the leading end of the ille. These teeth are preferably formed by milling and the forward face of each tooth, indicated at i3d, may j advantageously be disposed at substantially a right angle to the plane of the ille body. The

rear face lfib of each tooth is preferably disposed.Y

at an acute angle to the plane of the file. The centers about which the arcuate'teeth are generated are located one side of the central.

longitudinal axis of the file, in the case of the le illustrated the centers being located along the leading edge of the nle. With the tooth centers so located the angle between the leading edge of the file and a tangent to an arcuate tooth, at the point where such arcuate tooth terminates at such leading edge, is substantially a right angle. From the leading edge each arcuate tooth curves rearwardly of the le as shown and, where the tooth terminates at the trailing edge of the file the angle between such trailing edge and a tangent to the tooth at that point is approximately 37", as shown in Figure 3 of the drawings.

Each file tooth is divided by a plurality of notches into a Iplurality of arcuate lands and the notches and lands may be clearly seen in Figures 4 and 5, the notches being indicated at l3c and the individual. arcuate lands at i3d, l3e, l3f, 83g, lh and ifi-i. In this and other figures of the drawings the leading edge of the le is indicated by the numeral la and the trailing edge by the numeral it, The notches l3c are V-shaped and the walls or each meet at an angle of substantially 45. The straight line bottom of each notch, which is the line of intersection of the side walls of the notch, indicated at i3c, is disposed atV an angle of approximately 14 to the major axis of the le and, as will be observed in Figures l and 3, the inclined notches are arranged in rectilinear series, the leading notch of each series being at or closely adjacent the leading edge 0i the i'le and the learmost or terminal notch of each series being adjacent the trailing edge of the file,

Each rectilinear series of notches begins at a point immediately adjacent the leading edge,` or the leading end, of the nle and extends rear- I wardly from that point toward the handle end of the file, each series making an angle of preferably le", as will the walls and straight line bottoms of individual notches, if prolonged, with the longitudinal axis oi the -File, In the drawings the several series of notches are shown to be disposed in exact parallelism and to be equidistantly spaced. This arrangement is desirable but, without departure from the invention, slight variations may be made in order to more particularly adapt the file to the performance of ling operations of dii'erent character.

In any event each arcuate tooth of the file is divided into arcuate but shorter portions, or lands, Where the serios of notches are equidistantly spaced from each other, and are disposed in parallelism, the lands will vary in length, as shown in Figure 5, those lands toward the leading edge of the le being relatively short and the other lands increasing in length as the trailing edge of the ille is approached. Preferably the notches are out after the arcuate teeth have been formed and the cutting operation may ad- V'rantageously be performed by milling, broaching,

.eighths of an inch apart, measured axially of the ille, which is one inch Wide. With a file of this width, and where ,the tooth radius is one and fiveeighths inches, which is a preferred radius, the distance between each rectilinear series of notches and the adjacent series may be advantageously of an inch, rThe teeth are not notched entirely to the bottom, as clearly shown in Figures 4 and 5, although the notches may be made deeper if desired. In the general case it is only necessary to provide relatively shallow notches in order to accomplish the desired objectives.

When the file is in operation in the intended manner there will be a large number of teeth in Contact with each area of the Work, as may be readily perceived from an inspection of Figure i, and the contact with the work, simultaneously, ol` a larger number of teeth renders the ille much less likely to chatter than one in which the teeth are so arranged that a lesser number will be in contact with substantially the same area. This is an advantage of considerable importance particularly where, as in the case of the present intention, number of teeth in contact with the work is'made relatively large without sacrince in tooth size and coarseness so that full cutting ability of the file is maintained.

linasmuch as the lands of succeeding teeth are in echelon, or staggered with relation to each other, a maximum removal of stock from the work with a minimum pressure of the le against the work is realized. Possibility of clogging is reduced to a minimum because each tooth is broken up into a plurality of lands by the notches and a rela-tively short particle or piece of work is removed by each land. By reason of the configuration of the teeth and the centeringr of each about a point upon or adjacent the leading edge of the le, and provi-ding aligned series of notches in spaced relation as shown, the file will perform both roughing and finishing opera-tions upon a single stroke. This follows from the fact that teeth adjacent the leading edge have relatively small shearing angles, the lands adjacent this edge are shorter, and the cutting action is relatively coarse. Toward the trailing edge of the iile the shearing angle, i. e., the approximate angle which each land makes with the direction of movement of the le, is much less than at the opposite side, ultimately becoming approximately 37 instead of 90 as along the leading edge, the lands becoming longer and the `cutting action much finer. Likewise, along the leading edge of the file'the teeth are spaced apart more widely than they are along the trailing edge or, in other words, the iile is Vcoarser along its leading edge than along its trailing edge. This is because the teeth are curved about centers on a line parallel to but offset toward the leading edge of the file from the longitudinal axis thereof and naturally converge as the distance Yfrom the line of centers increases. Decrease in coarseness of the le from side to side is an important factor in giving it the capacity for roughing and nishing with the same stroke. Y

Disposition of the series of notches in the manner described likewise tends to prevent too great a lateral movement of the le on its working stroke, in the direction of its leading edge. Naturally, by reason of the general inclinations of the teeth the file will tend to move laterally (upwardly as shown in Figure 1) as it is moved forwardly. By reason of the provision of the inclined notches, and the inclined series oi notches,

. however, this tendency is counteracted to some path which he would naturally give it in ling any piece of work.

Files embodying the invention will, in the usual case, be formed substantially as described and illustrated. It is clear, however, that either edge may be made the leading edge, and for special reasons the teeth may be centered on the edge I6 and the lines of notches reversed in direction. When such a le is in use it will be so manipulated that the direction of bodily movement sidewise is also reversed. It will also be apparent to one well acquainted with the use of iiles that the novel le may be used as a roughing file if moved sidewise, while advancing, with that edge which is normally the trailing edge, in advance.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

An elongated double purpose iile having a ling surface comprising a multiplicity of arcuate cutting teeth spaced along the length of the le the convex sides of which face toward that end of the le which leads when the le is moved on its cutting stroke, the centers of curvature of said teeth being spaced from each other along a line substantially coinciding with one edge of said filing surface, yand substantially parallel lines of serrations each running through a plurality of said teeth from the trailing end oi said le and the edge thereof opposite said one edge at an angle toward said one edge and the leading end of said ile, dividing said :arcuate teeth into indivi-dual tooth cutting sections, so that the tooth sections adjacent said one edge thereof are relatively short, widely spaced and have small angles of shear so as to together constitute an elongated coarse cutting or roughing area, and the tooth sections adjacent the opposite edge of the le are longer, closer together and have larger angles of shear than those of the roughing area and together constitute an elongated surface finishing area, whereby the file when moved forwardly upon a cutting stroke and given a simultaneous lateral movement with the roughing area in advance of the nishing area, will rst rapidly remove stock from a given area of a Work piece and, during the saine stroke, will immediately thereafter finish iile such portion.

EDWARD BLAIR LE FE1/RE.

REFERENCES CITED The following references are of record in the of this patent:

UNITED STATES PATENTS 

